Electro-copper plating apparatus

ABSTRACT

Disclosed herein is an electro-copper plating apparatus in which a cathode, an insoluble anode, a copper ball, and a plating solution are included in a single bath, wherein the plating solution includes manganese oxide; or an electro-copper plating apparatus including: a main bath including a cathode, an insoluble anode, and a plating solution; and a dissolution bath including a copper ball, and manganese oxide. According to the present invention, the manganese oxide having higher oxidation-reduction potential instead of using Fe 3+  of the related art as the copper source in the electro-copper plating apparatus may be used to obtain a high effect in suppressing surface plating even at a low concentration.

CROSS REFERENCE(S) TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. Section 119 ofKorean Patent Application Serial No. 10-2012-0100969, entitled“Electro-Copper Plating Apparatus” filed on Sep. 12, 2012, which ishereby incorporated by reference in its entirety into this application.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to an electro-copper plating apparatus.

2. Description of the Related Art

An insoluble anode is used to minimize a foreign material when meltingand using copper (Cu) in an electro-copper plating method. Theelectro-copper plating method using the insoluble anode may be largelyclassified into two methods according to a scheme of supplying thecopper, that is, a method of supplementing CuO with a plating solutionand a method of dissolving Fe³⁺ ion in the plating solution to supply acopper ion to a main bath.

FIG. 1 shows an electro-copper plating apparatus using an insolubleanode formed by a CuO supplement scheme, which is a scheme in which Cuconsumed by a plating reaction in the main bath 10 is supplemented byputting CuO 15 powder into a separate dissolution bath 14, dissolvingthe input material by air agitation, or the like, and recirculating thematerial to the main bath 10. Here, the main bath 10 includes a cathode11 and an anode 12, and inorganic materials of copper sulfate/sulfuricacid/chlorine are used as main components of the plating solution 13.

FIG. 2 shows an electro-copper plating apparatus using an insolubleanode formed by a Fe³⁺ scheme, which is a scheme in which when Cuconsumed by a plating reaction in the main bath 10 is supplemented as acopper ion by putting a pure copper ball 25 into a plating solution of aseparate dissolution bath 24, and circulating the input material to meltthe copper ball 25 by a spontaneous reduction reaction of Fe³⁺ 26. Here,the main bath 20 includes a cathode 21 and an anode 22, and inorganicmaterials of copper sulfate/sulfuric acid/chlorine are used as maincomponents of the plating solution 23.

Two schemes have been generally used in vertical and horizontal platinginstallation schemes. However, in the case of CuO, an efficiency ofsupplementing CuO is deteriorated due to an introduction of inorganicand organic impurities, and in the case of Fe³⁺, there is a limitationin improvement/reconstruction due to an exclusive scheme of a specificcompany, such that a development of an apparatus capable of replacingtwo schemes has been required.

RELATED ART DOCUMENT

(Patent Document 1) JP Patent Laid-Open Publication No. 2008-513985

SUMMARY OF THE INVENTION

An object of the present invention is to provide a novel electro-copperplating apparatus capable of replacing the electro-copper platingapparatus using an insoluble anode of the related art without generatingproblems of the electro-copper plating apparatus using an insolubleanode of the related art.

According to a first exemplary embodiment of the present invention,there is provided an electro-copper plating apparatus in which acathode, an insoluble anode, a copper ball, and a plating solution areincluded in a single bath, wherein the plating solution includesmanganese oxide.

The manganese oxide may be KMnO₄ or NaMnO₄.

The manganese oxide may be included in a concentration of 0.1 to 10 g/L.

The plating solution may include copper sulfate in a concentration of 50to 350 g/L, sulfuric acid in a concentration of 10 to 150 g/L, andchlorine in a concentration of 10 to 200 mg/L.

The insoluble anode may be made of titanium (Ti) coated with platinum(Pt) or IrO₂.

According to a second exemplary embodiment of the present invention,there is provided an electro-copper plating apparatus including: a mainbath including a cathode, an insoluble anode, and a plating solution;and a dissolution bath including a copper ball, and manganese oxide.

The copper may be supplied from the dissolution bath to the platingsolution of the main bath by dissolving the copper to be a copper ionthrough a reaction of manganese oxide and the copper ball of thedissolution bath.

The manganese oxide may be KMnO₄ or NaMnO₄.

The manganese oxide may be included in a concentration of 0.1 to 10 g/L.

The plating solution of the electro-copper plating apparatus may includecopper sulfate in a concentration of 50 to 350 g/L, sulfuric acid in aconcentration of 10 to 150 g/L, and chlorine in a concentration of 10 to200 mg/L.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an electro-copper plating apparatus using an insolubleanode formed by a CuO supplement scheme of the related art;

FIG. 2 shows an electro-copper plating apparatus using an insolubleanode formed by a Fe³⁺ scheme of the related art; and

FIGS. 3 and 4 show an electro-copper plating apparatus using aninsoluble anode according to an embodiment of the present embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be described in detail.

Terms used in the present specification are for explaining theembodiments rather than limiting the present invention. Unlessexplicitly described to the contrary, a singular form includes a pluralform in the present specification. The word “comprise” and variationssuch as “comprises” or “comprising,” will be understood to imply theinclusion of stated constituents, steps, operations and/or elements butnot the exclusion of any other constituents, steps, operations and/orelements.

The present invention relates to an electro-copper plating apparatususing an insoluble anode. The electro-copper plating apparatus accordingto a preferred embodiment of the present invention is shown in FIG. 3.

Referring to FIG. 3, in the electro-copper plating apparatus, a cathode111, an insoluble anode 112, a copper ball 115, and a plating solution113 are included in a single bath 110, wherein the plating solution 113includes manganese oxide 116.

The electro-copper plating apparatus according to FIG. 1 has a structurein which all components for electro-copper plating are included in onebath 110.

In the electro-copper apparatus, the cathode 111 is a material to beplated to thereby be electro-copper plated, which may be a printedcircuit board having a panel shape.

In addition, the insoluble anode 112 may be made of a material, that is,titanium (Ti) coated with platinum (Pt) or IrO₂, and may be used tothereby minimize a foreign material when performing a plating process byusing copper.

Further, a copper plating solution used in the electro-copper platingincludes copper sulfate in a concentration of 50 to 350 g/L, sulfuricacid in a concentration of 10 to 150 g/L, and a chlorine ion in aconcentration of 10 to 200 mg/L. In particular, the present inventionincludes a manganese oxide having strong oxidizing power as a componentfor supplying Cu of the insoluble anode.

The manganese oxide may be KMnO₄ or NaMnO₄. The manganese oxide servesto produce a copper ion by dissolving the copper ball. In addition,KMnO₂, which is a by-product produced after the above-describedreaction, is re-oxidized to KMnO₄ and reproduced. The manganese oxidefunctions on a surface of the cathode, which is a material to be plated,to suppress a plating effect.

The manganese oxide is preferably included in a concentration of 0.1 to10 g/L. In the case in which the concentration of the manganese oxide isless than 0.1 g/L, an effect of suppressing surface plating is notsufficient which may not obtain throwing power, and in the case in whichthe concentration of the manganese oxide is more than 10 g/L, athickness of a plated surface is not sufficient or a plating process isnot completely performed due to an excessive effect of suppressingsurface plating, which is not preferred.

In addition, copper sulfate included in the plating solution may beincluded in a form of pentahydrate. In the case in which theconcentration of copper sulfate is significantly low, since anefficiency of a cathode current is deteriorated, the concentrationthereof is preferably 50˜350 g/L in order to obtain a stable platingefficiency.

Further, in the plating solution, it is preferable that the sulfuricacid is included in a concentration of 10˜150 g/L to increaseconductance and smoothly flow an electric current.

In addition, the chlorine ion in the plating solution may be included inHCl or KCl form, and it is preferable to be included in a concentrationof 10 to 200 mg/L in order to clearly show a smoothing effect combinedwith an additive.

Further, the electro-copper plating apparatus according to anotherpreferred embodiment of the present invention is shown in FIG. 4.Referring to FIG. 4, the electro-copper plating apparatus includes amain bath 120 including a cathode 121, an insoluble anode 122, and aplating solution 123; and a dissolution bath 124 including a copper ball125, and manganese oxide 126.

According to the embodiment, the electro-copper plating apparatus has astructure in which the cathode 121, the insoluble anode 122, and theplating solution 123 are included in the main bath 120, and the copperball 125 and the manganese oxide 126 are separately included in thedissolution bath 124 in order to supply copper.

Therefore, when the copper ball 125 is put into the dissolution bath124, the copper ball 125 is dissolved to be a copper ion by manganeseoxide 126 to thereby be supplied to the plating solution 123 of the mainbath 120. In addition, KMnO₂, which is a by-product produced after theabove-described reaction, is re-oxidized to KMnO₄ in the anode 122 ofthe main bath 120 and reproduced. Therefore, the manganese oxidefunctions on a surface of the cathode 121, which is a material to beplated, to suppress a plating effect.

In the electro-copper apparatus, the cathode 121 is a material to beplated to thereby be electro-copper plated, which may be a printedcircuit board having a panel shape.

In addition, the insoluble anode 122 may be made of a material, that is,titanium (Ti) coated with platinum (Pt) or IrO₂, and may be used tothereby minimize a foreign material when performing a plating process byusing copper.

In addition, a copper plating solution used in the electro-copperplating includes copper sulfate in a concentration of 50 to 350 g/L,sulfuric acid in a concentration of 10 to 150 g/L, and a chlorine ion ina concentration of 10 to 200 mg/L. In particular, the present inventionincludes a manganese oxide having strong oxidizing power as a componentfor supplying Cu of the insoluble anode.

The manganese oxide is KMnO₄ or NaMnO₄, and preferably included in aconcentration of 0.1 to 10 g/L. In the case in which the concentrationof the manganese oxide is less than 0.1 g/L, an effect of suppressing aplating of a surface is not sufficient which may not obtain throwingpower, and in the case in which the concentration of the manganese oxideis more than 10 g/L, a thickness of a plated surface is not sufficientor a plating process is not completely performed due to an excessiveeffect of suppressing a surface plating, which is not preferred.

In this case, a reaction in the insoluble anodes 112 and 122 isrepresented by the following reaction formula 1:

Mn²⁺+4H₂O→MnO₄ ⁻+8H⁺+5e ⁻

Mn²⁺+2H₂O→MnO₂ ⁻+4H⁺+2e ⁻  [Reaction Formula 1]

In addition, a reaction in the cathodes 111 and 121 is represented bythe following reaction formula 2:

MnO₄−+8H⁺+5e ⁻→Mn²⁺+4H₂O Eo=+1.51V

Cu²⁺+2e ⁻→Cu Eo=+0.34V  [Reaction Formula 2]

Further, a reaction of generating the copper ion is represented by thefollowing reaction formula 3: The reaction below is reacted in thedissolution bath having a structure in which the main bath and thedissolution bath are separately formed.

2MnO₄ ⁻+16H⁺+5Cu→2Mn²⁺+5Cu²⁺+8H₂O  [Reaction Formula 3]

In the present invention, since an oxidation-reduction potential ofmanganese oxide used as a copper source is +1.51V, which is higher thanthat of Fe³⁺/Fe²⁺, that is, +0.77V, a high effect in suppressing surfaceplating may be obtained even at a low concentration.

According to the present embodiment, the manganese oxide having higheroxidation-reduction potential instead of using Fe³⁺ of the related artas the copper source in the electro-copper plating apparatus may be usedto obtain a high effect in suppressing surface plating even at a lowconcentration. In addition, the plating rate of the surface may besuppressed in the structure such as a through hole or a blind via holethan the inner portion of the hole to improve the throwing power.

What is claimed is:
 1. An electro-copper plating apparatus in which acathode, an insoluble anode, a copper ball, and a plating solution areincluded in a single bath, wherein the plating solution includesmanganese oxide.
 2. The electro-copper plating apparatus according toclaim 1, wherein the manganese oxide is KMnO₄ or NaMnO₄.
 3. Theelectro-copper plating apparatus according to claim 1, wherein themanganese oxide is included in a concentration of 0.1 to 10 g/L.
 4. Theelectro-copper plating apparatus according to claim 1, wherein theplating solution includes copper sulfate in a concentration of 50 to 350g/L, sulfuric acid in a concentration of 10 to 150 g/L, and chlorine ina concentration of 10 to 200 mg/L.
 5. The electro-copper platingapparatus according to claim 1, wherein the insoluble anode is made oftitanium (Ti) coated with platinum (Pt) or IrO₂.
 6. An electro-copperplating apparatus comprising: a main bath including a cathode, aninsoluble anode, and a plating solution; and a dissolution bathincluding a copper ball, and manganese oxide.
 7. The electro-copperplating apparatus according to claim 6, wherein the copper is suppliedfrom the dissolution bath to the plating solution of the main bath bydissolving the copper to be a copper ion through a reaction of manganeseoxide and the copper ball of the dissolution bath.
 8. The electro-copperplating apparatus according to claim 6, wherein the manganese oxide isKMnO₄ or NaMnO₄.
 9. The electro-copper plating apparatus according toclaim 6, wherein the manganese oxide is included in a concentration of0.1 to 10 g/L.
 10. The electro-copper plating apparatus according toclaim 6, wherein the plating solution of the electro-copper platingapparatus includes copper sulfate in a concentration of 50 to 350 g/L,sulfuric acid in a concentration of 10 to 150 g/L, and chlorine in aconcentration of 10 to 200 mg/L.